London   - As a group of young anti-Brexit activists from Northern Ireland met opposition figures at the British parliament on Wednesday, embattled Prime Minister Theresa May was answering questions nearby in the Commons, parliament's main elected house.

As with so many debates in the parliament, in the British media and across the whole country for the past two years, the tortuous process of extricating Britain from the European Union was the topic of the day.

"There will be no second referendum," May told lawmakers. "The people voted [in the 2016 Brexit referendum] and this government will deliver on it." The youngsters visiting parliament couldn't disagree more. They were from Our Future, Our Choice NI, a campaign group pushing for "a people’s vote, led by young people from across Northern Ireland." "For my generation, there is no greater threat than Brexit," Doire Finn, 23, from the Northern Irish town of Newry, close to the border with Ireland, says in the group's campaign video.

Supporting the Voice of the People campaign

Northern Ireland is at the centre of the Brexit negotiations, as the two sides try to ensure an open border between Northern Ireland - which is part of Britain - and the Republic of Ireland. After decades of bitter conflict in the late 20th century, many people fear that any change to the status of the border could damage Northern Ireland's fragile peace process. "We have never witnessed the terrible violence of the past," said Finn's unnamed 16-year-old colleague. "Brexit threatens all of that and no young person wants to dragged back to that." "Yet we are completely ignored," Finn added.

May's intransigence on the issue of a second referendum has not deterred pro-EU lawmakers from all parties and hundreds of thousands of members of the public from backing the People's Vote campaign for a referendum on the final outcome of her fraught Brexit negotiations with the EU. People's Vote says some 100,000 supporters attended its rally in June. It hopes Saturday's march will be "bigger and better." London Mayor Sadiq Khan from the main opposition Labour Party; Liberal Democrat leader Vince Cable; and pro-EU lawmakers Anna Soubry and Sarah Wollaston from May's own Conservative party are among those scheduled to address the marchers.

May said on Thursday that she had floated the idea of extending the planned 21-month Brexit transition period by an extra year, during an EU leaders' summit in Brussels.

Soubry said May was forced to make the offer because her government is divided over a "backstop" to guarantee an open Irish border and has failed to secure a future trade deal with the EU before Britain leaves the bloc in March.

"More broken Brexit promises," Soubry tweeted, urging people to join Saturday's march. In his message to the marchers, Khan said May was taking Britain "towards either a bad Brexit deal or - worse still - no deal at all." "Both these scenarios are a million miles from what was promised," he said.

Pressure for a second referendum

Nearly 900,000 people have signed an online petition for a second referendum that was started by The Independent newspaper. That number may sound big, but May reminded her pro-EU critics on Wednesday that "17.4 million people voted to leave the EU." A majority of 52 per cent voted to leave the European Union in June 2016, with a turnout of 72 per cent of the 46.5 million eligible voters. People's Vote has published no detailed plans on how it would organize another vote, what the questions would be, or how the result of two votes would be reconciled.

It has warned that the EU could say goodbye to Britain in March with a commitment to continue talks and a "warmly worded, yet specifics-free, political declaration about future relationships." This "blind Brexit" would leave Britain in "the same place as a 'no deal' Brexit, but without the clarity," said Labour lawmaker Chris Leslie. Crucially, Labour's left-wing leader Jeremy Corbyn will not address the People's Vote rally on Saturday.

Corbyn and other senior Labour figures fear the party could lose parliamentary seats if it backs a new vote, because majorities in many of its constituencies, especially in northern and central England, backed Leave in 2016. "The People’s Vote campaign will go nowhere until it starts to talk to Leave voters and address their legitimate grievances," Simon Hix, a political scientist at the London School of Economics, wrote on Twitter last week.